    /** 文件名: https://github.com/liuqun/openssl-sm4-demo/blob/cmake/src/main.c */
    #include <stddef.h>
    #include <stdio.h>
    #include <stdlib.h>
    #include <string.h>
    #include "openssl/err.h"
    #include "openssl/evp.h"
     
    /* Before OpenSSL 1.1.1-pre1, we did not have EVP_sm4_ecb() */
    #if defined(OPENSSL_VERSION_NUMBER) \
        && OPENSSL_VERSION_NUMBER < 0x10101001L
    static const EVP_CIPHER *(*EVP_sm4_ecb)()=EVP_aes_128_ecb;
    #endif
     
    typedef struct {
        const unsigned char *in_data;
        size_t in_data_len;
        int in_data_is_already_padded;
        const unsigned char *in_ivec;
        const unsigned char *in_key;
        size_t in_key_len;
    } test_case_t;
     
     
    void test_encrypt_with_cipher(const test_case_t *in, const EVP_CIPHER *cipher)
    {
        unsigned char *out_buf = NULL;
        int out_len;
        int out_padding_len;
        EVP_CIPHER_CTX *ctx;
     
        ctx = EVP_CIPHER_CTX_new();
        EVP_EncryptInit_ex(ctx, cipher, NULL, in->in_key, in->in_ivec);
     
        if (in->in_data_is_already_padded)
        {
            /* Check whether the input data is already padded.
            And its length must be an integral multiple of the cipher's block size. */
            const size_t bs = EVP_CIPHER_block_size(cipher);
            if (in->in_data_len % bs != 0)
            {
                printf("ERROR-1: data length=%d which is not added yet; block size=%d\n", (int) in->in_data_len, (int) bs);
                /* Warning: Remember to do some clean-ups */
                EVP_CIPHER_CTX_free(ctx);
                return;
            }
            /* Disable the implicit PKCS#7 padding defined in EVP_CIPHER */
            EVP_CIPHER_CTX_set_padding(ctx, 0);
        }
     
        out_buf = (unsigned char *) malloc(((in->in_data_len>>4)+1) << 4);
        out_len = 0;
        EVP_EncryptUpdate(ctx, out_buf, &out_len, in->in_data, in->in_data_len);
        if (1)
        {
            printf("Debug: out_len=%d\n", out_len);
        }
     
        out_padding_len = 0;
        EVP_EncryptFinal_ex(ctx, out_buf+out_len, &out_padding_len);
        if (1)
        {
            printf("Debug: out_padding_len=%d\n", out_padding_len);
        }
     
        EVP_CIPHER_CTX_free(ctx);
        if (1)
        {
            int i;
            int len;
            len = out_len + out_padding_len;
            for (i=0; i<len; i++)
            {
                printf("%02x ", out_buf[i]);
            }
            printf("\n");
        }
     
        if (out_buf)
        {
            free(out_buf);
            out_buf = NULL;
        }
    }
     
    void main()
    {
        int have_sm4 = (OPENSSL_VERSION_NUMBER >= 0x10101001L);
        int have_aes = 1;
        const unsigned char data[]=
        {
            0x01, 0x23, 0x45, 0x67, 0x89, 0xab, 0xcd, 0xef,
            0xfe, 0xdc, 0xba, 0x98, 0x76, 0x54, 0x32, 0x10,
        };
        unsigned char ivec[EVP_MAX_IV_LENGTH]; ///< IV 向量
        const unsigned char key1[16] = ///< key_data, 密钥内容, 至少16字节
        {
            0x01, 0x23, 0x45, 0x67, 0x89, 0xab, 0xcd, 0xef,
            0xfe, 0xdc, 0xba, 0x98, 0x76, 0x54, 0x32, 0x10,
        };
        test_case_t tc;
     
        tc.in_data = data;
        tc.in_data_len = sizeof(data);
        tc.in_data_is_already_padded = (tc.in_data_len % 16)==0; // Hard coded 16 as the cipher's block size
        tc.in_key = key1;
        tc.in_key_len = sizeof(key1);
        memset(ivec, 0x00, EVP_MAX_IV_LENGTH);
        tc.in_ivec = ivec;
     
    #if defined(OPENSSL_NO_SM4)
        have_sm4 = 0;
    #endif
        if (have_sm4)
        {
            printf("[1]\n");
            printf("Debug: EVP_sm4_ecb() test\n");
            test_encrypt_with_cipher(&tc, EVP_sm4_ecb());
        }
    #if defined(OPENSSL_NO_AES)
        have_aes = 0;
    #endif
        if (have_aes)
        {
            printf("[2]\n");
            printf("Debug: EVP_aes_128_ecb() test\n");
            test_encrypt_with_cipher(&tc, EVP_aes_128_ecb());
        }
    }